Sample MT I answer key

Sample MT I answer key - Biological Sciences 101 Dr. Mark...

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Biological Sciences 101 Dr. Mark Sanders SAMPLE MIDTERM I ANSWER KEY 1. There are two acceptable answers to this question. One proposes a two gene system with epistasis, and the other a one gene system with incomplete dominance. The keys for each answer are given below. Two gene answer: 1a. Two genes are involved in the production of iris flower color. The interaction of two genes produces recessive epistasis that leads to a 9:3:4 ratio of plant flower color phenotypes . 1b. Red plants are aaBB, blue plants are AAbb, and purple plants are AaBb . 1c. Expected number of purple = (168)(9/16) = 94.5, red = (168)(4/16) = 42, blue = (168) (3/16) = 31.5. There are 2 degrees of freedom. The chi square value is, (94-94.5) 2 /94.5 + (31-31.5) 2 /31.5 + (43-42) 2 /42 = 0.035. The p value is > .975. We fail to reject the genetic hypothesis. One gene answer: 1a. One gene is responsible for iris flower color. Homozygotes for one allele (A 1 A 1 ) are red, homozygotes for the other allele (A 2 A 2 ) are blue, and heterozygotes (A 1 A 2 ) are purple. The ratio among the F 2 is a 1:2:1 ratio produced by the cross of heterozygous F 1 plants. 1b. Red plants are A
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Sample MT I answer key - Biological Sciences 101 Dr. Mark...

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